The Preparation of MgB₂ Conductors for Magnet Application of SMES in WST

Due to the low cost, high critical current density (J(c)), low anisotropy and a critical temperature of about 40 K, MgB2 tapes/wires is promising to operate in the High-temperature Superconducting Magnetic Energy Storage (SMES). Based on the development of the world's first 10 MJ/5 MW class High-temperature SMES prototype in China Southern Power Grid, the MgB2 wires prepared in Western Superconducting Technologies (WST) Co., Ltd is used to wind coils. This paper mainly introduces the preparation progress of MgB2 wires in WST. The round MgB2 wires consisted of 30 superconducting filaments and 7 copper filaments is prepared by In-situ PIT (Powder in Tube) technology, the metals (Nb, Cu and CuNi alloys) acted as stable matrix. For batch prepared MgB2 wires, the length of single one was greater than 2000 m, the MgB2 fraction of wires was 0.15, the average J(c) value of wires reached to 3265 A/mm(2) (4.2 K, 3 T). The tensile strength was more than 800 MPa. In addition, the decrement of I-c value is less than 2% for the single MgB2 wire after stranding.